What is Sin?
In Islam sin is doing anything that goes against the will of God. There are many names given to thoughts and actions that represent sin. However, the ones that are considered ?sin? in general and most frequently associated with sin in the Quran are the following three:

Ithm (plural: atham; meaning: crime, misdeed, offence) ? In all cases, Muslim scholars** agree that this word is used exclusively for Sin. This is the sin that requires punishment, and only can be forgiven by repentance and God?s Mercy.

Eschew all sin [ithm]*, open or secret: those who earn sin will get due recompense for their "earnings." Quran 6:120

Dhanb ( plural: dhanub; meaning: offence, crime, misdeed) ? In some cases Muslims translate not as ?sin? but as ?fault?. For example the Muslim translator Shakir translates this word as ?fault? most of the time. Other Muslim translators translate this word as ?sin? except when it refers to ?prophets? and then it is translated as ?fault?. Pickthall, another renowned Muslim translator does translate is more consistently as ?sin?.

Does God accept righteous works even when we sin?
Islamic scholars say that God is able to overlook and/or forgive sins when accompanied by righteous works. Muslim scholars explain that God does not punish because God?s mercy exceeds his justice, when it is also accompanied by faith in Islam.

But those who believe and work deeds of righteousness, and believe in the (Revelation) sent down to Muhammad - for it is the Truth from their Lord,- He will remove from them their ills and improve their condition. Quran 47:2

Those who believe and work righteous deeds,- from them shall We blot out all evil (that may be) in them, and We shall reward them according to the best of their deeds. Quran 29:7

Question to consider: In the Surah 3:84 below we see God does not make a distinction between any of his revelations. Is not the above verse making a distinction?

We believe in Allah, and in what has been revealed to us and what was revealed to Abraham, Ismail, Isaac, Jacob, and the Tribes, and in (the Books) given to Moses, Jesus, and the Prophets, from their Lord: We make no distinction between one and another among them - Quran 3:84.

Are they multiple categories of sins?
Islamic scholars have come up with Major and Minor sins based on the teachings of the Quran. In general, scholars separate major sins as those committed against others, while minor ones are those that are just between God and man, and not with another person. However sins of unbelief and shirk (associating partner with God) are considered major. In addition, minor sins are either pre-meditated or by mistake, while major ones are considered to be deliberate. In some sects of Islam, a single major sin will result in a Muslim becoming an unbeliever. This is not the case with orthodox Islam.

If ye (but) eschew the most heinous of the things which ye are forbidden to do, We shall expel out of you all the evil in you, and admit you to a gate of great honour. Quran 4:31

Question to consider: Since the Quran states that the person who sins earns hell fire than how come here the Quran is expelling evil without hell fire being a consequence?

Is there consequence for Sin?
Islamic scholars says that the remedy for ?dhanb? is to remove the action that is the cause, and for ?ithm? is to repent and seek forgiveness. The Quran is clear however, that both are punishable by him.

Islamic scholars says that the remedy for ?dhanb? is to remove the action that is the cause, and for ?ithm? is to repent and seek forgiveness. The Quran is clear however, that both are punishable by him.

Those who unjustly eat up the property of orphans, eat up a Fire into their own bodies: They will soon be enduring a Blazing Fire! Quran 4:10

Those who conceal Allah's revelations in the Book, and purchase for them a miserable profit,- they swallow into themselves naught but Fire; Allah will not address them on the Day of Resurrection. Nor purify them: Grievous will be their penalty. Quran 2:174

If God were to punish men for their wrong-doing, He would not leave, on the (earth), a single living creature: but He gives them respite for a stated Term: When their Term expires, they would not be able to delay (the punishment) for a single hour, just as they would not be able to anticipate it (for a single hour). Quran 16:61

If God were to punish men according to what they deserve. He would not leave on the back of the (earth) a single living creature: but He gives them respite for a stated Term: when their Term expires, verily God has in His sight all His Servants. Quran 35:45

Question to consider: Do not these above verses say that all of us are doomed because we all sin and deserve hell fire? In other places the Quran says that righteous deeds nullify some sins. Therefore is the Quran not inconsistent in its teaching?

What is the Source of Sin?
The Quran states that the Satan?s pattern of temptation of man in general is the same as that of Adam. God decrees a law for man but instead man obeys his own desires and does not guard himself. Satan?s deception along with man?s fate causes him to sin. Man therefore becomes justifiably liable to God?s judgment and wrath.

O ye Children of Adam! Let not Satan seduce you, in the same manner as He got your parents out of the Garden, stripping them of their raiment, to expose their shame: for he and his tribe watch you from a position where ye cannot see them: We made the evil ones friends (only) to those without faith. Quran 7:27

Question to consider: If God himself makes Satan friendly with those without faith, is that not causing those to never have faith? If so, how can a ?just? God hold them accountable for their sin?